Combining themes?

While I know a little HTML, I have no idea how to do any CSS coding. So if my question makes no sense, please tell me.

I’ve recently started a webcomic using the graphic novel theme (http://comicpress.org/demo-gn/) but, as you can see, it’s very simple and kind of boring. So, in a flash of (debatable) genius I wondered: is it possible to merge two themes?

For example; I think the theme ‘Moonlight’ (http://wordpress.org/extend/themes/moonlight) is very pretty. But for ease of updating I need to be able to keep the Comicpress template fairly intact. Is there a way that I could easily remove the color theme, header, and sidebar style from Moonlight and paste it to Comicpress?

I have a feeling that my idea is crazy and impossible, so if it is could anyone point me to a good CSS walkthrough? I at least need to learn how to change the background and my google searches seem to be failing me at the moment.

I am attempting almost exactly the same…I want to use a customized Pixel/deFusion(or similar) theme(s) in conjunction with ComicPress “pages”. Have found some tips like this one…http://wordpress.org/support/topic/234077?replies=8
Please let me know if you find anything. As I will do the same. Thank you.